| Objective: To investigate changes of heme oxygenase-1 (HO-1) in cardiomyocytes after acute myocardial infarction and the impact of simvastatin on HO-1 expression in rats.Methods: Myocardial infarction models were made by anterior descending coronary artery ligation on male SD rats whereas sham group by spurious ligation( Sham, n=24). Survivals were randomized into myocardial infarction( MI, n=24) group and simvastatin( Sim, n=24) group 24 hours after operation. Sim group was treated with simvastatin 40mg·kg-1·d-1 via gavage till sacrifice. MI and Sham gourps were gavaged with equal volume of 0.9%NaCl at the same time. Rats were sacrificed at time points of 24 hours, 7 days and 28 days after operation( n=8 for each group at each time point), for the detection of HO-1 mRNA by RT-PCR, HO-1 protein level by Western Bolt, activity of superoxide dismutase (SOD) and content of malondialdehyde (MDA) by spectrophotometric method in non-infarcted zone.Results: Expression of HO-1 mRNA and protein level increased at 24 hours, peaked at 7 days and decreased to basal levels at 28 days. All the indexes at each time point mentioned above were significantly higher in MI group than those in Sham group. At 7 days and 28 days (P<0.05), the indexes were higher in Sim group than those in MI group (P<0.05). Activity of SOD was increased while content of MDA was decreased in Sim group than those in MI group at 7days and 28days.Conclusion: The expression of HO-1 changes dynamically within 28 days after acute myocardial infarction. One of the possible mechanism of simvastatin's antioxidative cardiac protection may be through the induction of HO-1.
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